In order to communicate information between computers, computer networks are utilized. Many computer networks operate according to a set of layered protocols, called a network model. One network model is generally described in the Open Systems Interconnection (OSI) Reference Model. The OSI Reference Model is generally described in more detail in Section 1.1 of the reference book entitled Interconnections Second Edition, by Radia Perlman, published September 1999, which is hereby incorporated by reference as though fully set forth herein. Another popular network model is the TCP/IP model. This description will focus on the OSI model, although it is equally applicable to other network models, such as the TCP/IP model. The OSI model defines a physical layer (layer 1), a data-link layer (layer 2), an internetwork layer (layer 3), a transport layer (layer 4), and several other layers. Each layer adds a header (and optionally a footer) to a packet of data from the next lower layer. One popular protocol is the Ethernet protocol, which operates across layers 1 and 2. Ethernet systems assign unique Media Access Control (MAC) addresses to network devices. One popular layer 3 protocol is the Internet Protocol (IP). The IP protocol assigns IP addresses to network devices.
In order to connect Customer Premises Equipment (CPE) to the Internet, a client will generally connect through an Access Service Provider (ASP) to an Internet Service Provider (ISP), which provides a connection to the Internet. Although the ISP and ASP are sometimes under the control of a single entity, they are sometimes under the control of distinct entities. The CPE will contain some sort of access device, such as a modem, a DSL modem, a cable modem, or a direct Ethernet interface. The access device will then typically establish a connection to an Access Module provided by the ASP (although this step may be omitted in the case of a direct Ethernet interface). This Access Module may be, for example, a DSLAM in the case of a DSL connection. The Access Module will then transmit signals from the CPE across a local network eventually ending up at a Broadband Remote Access Server (BRAS) under the control of an ISP. The BRAS serves as a gateway to the Internet. The local network of the ASP typically operates as a layer 2 network, ignoring layer 3 and subsequent layer headers. The BRAS acts as a router, which utilizes layer 3 data. Multiple ISPs will sometimes contract with a single ASP to provide access to clients. Various layer 3 services, such as Voice Over IP (VOIP) and Video on Demand (VOD) may be provided over the Internet. Sometimes, an ASP will desire to provide these services directly to clients over the local access network. One prior art approach to add these layer 3 services into the layer 2 network of the ASP is to position VOIP and VOD servers along a layer 3 edge of the network. In order to accomplish this, the CPE must be programmed to serve as a router, and it must be able to route packets directly to these servers in addition to the packets that it routes to the BRAS.